Browsing by Issue Date, starting with "2025-01"
Now showing 1 - 10 of 54
Results Per Page
Sort Options
- Preparation and characterization of Santa Barbara Amorphous-15 particles functionalized with mercaptopropyl groups and of their composites with poly(lactic acid)Publication . Díez-Rodríguez, Tamara M.; Blázquez-Blázquez, Enrique; Martínez, Juan C.; Lourenço, João P.; Cerrada, María L.; Pérez, ErnestoSanta Barbara Amorphous-15 (SBA-15) particles functionalized with mercaptopropyl groups (named as SBASH) have been prepared by a synthetic one-pot approach, and then have been incorporated into poly(lactic acid) (PLA), comparing their characteristics with those shown by composites attained with neat SBA-15 (PLASBA). The silica including the mercaptopropyl groups exhibits a certain loss of regularity because of its functionalization, although displays a better interaction with PLA than the pristine SBA-15 particles in the resulting materials. These composites (PLASBASH and PLASBA) also show a thermal stability slightly higher than neat PLA. An important nucleation effect of SBASH silica in the crystallization of PLA has been deduced from cooling experiments as well as from the cold crystallization in heating runs and from the degree of crystallinity reached. Small Angle X-ray Scattering (SAXS) profiles show that the PLA long spacings are rather similar for the different composites and the neat PLA. Thus, crystal size is rather similar in all samples. Microhardness values show an evident effect of reinforcement in all the composites compared with that shown by neat PLA. Nevertheless, the increase in rigidity is smaller in the biobased PLASBASH composites, those containing the modified silica, than in the PLASBA materials with the pristine SBA-15 particles.
- Predicting gear used in a multi-gear coastal fleetPublication . Leitão, Pedro; Campos, Aida; Castro, MargaridaKnowledge of the gear used in multi-gear fisheries is crucial for supporting fisheries management. Still, the high complexity and lack of data in the Portuguese multi-gear coastal fleet compromise this task. The present study developed a method to predict main fishing gear used in each fishing trip for the Portuguese multi-gear coastal fleet based on landing records (species caught, port, and month of landing). Landing records were used to predict gear (available for part of the fleet with electronic logbooks) using a machine learning model (random forest). This model was then applied to the remaining trips of the fleet, without electronic logbooks, to predict the gear used. A total of six gear types were considered: bivalve dredges, traps, gillnets, trammel nets, drifting longlines, and bottom longlines. The overall model prediction error was 14 %; bivalve dredges and longlines had the lowest errors, and trammel nets and gillnets were the highest. The study sheds new light on important aspects of the dynamics of this fleet, namely a decreasing trend in the use of longlines, poor electronic logbook coverage for some gear types, and greater diversity in the catches obtained with nets compared to other gear types.
- Designing a coastal monitoring marine biodiversity survey, using trammel nets and gillnets in PortugalPublication . Rufino, Marta M.; Maia, Catarina; Dinis, David; Farias, Inês; Moura, Teresa; Gomes, Pedro; Quaresma, Ivania; Martins, Rogélia; Figueiredo, Ivone; Serra-Pereira, Bárbara; Gaspar, Miguel; Moreno, AnaAlthough coastal areas are of great importance, they often lack long term monitoring surveys, which are essential for effective management, fisheries sustainability, and marine spatial planning. To address this, we conducted two experimental surveys aimed at assessing communities and their biodiversity, with the objective of designing a monitoring program for marine coastal biodiversity, based on gear type, depth, sampling arrangement, total net length, and panel position within the haul. Depth was found to be the most important factor shaping biodiversity, while gear type had the greatest impact on assessing species richness. Overall, both number of species and diversity increased with depth, though significant differences were only found between hauls deployed at 10 m and deeper (30-50 m). Trammel nets caught a larger number of species compared to gillnets, and there was evidence of an interaction between depth and gear, in terms of abundance and at the community level; samples taken deeper than 10 m showed more gear-related differences. We found that neither the panel position within the haul nor the number of nets had any impact on species diversity or abundance. Similarly, there was no evidence for an effect related to the arrangement of nets, as results were consistent whether using separated or continuous net panels. However, the number of nets used as a sampling unit significantly influenced the results, as the variation in species abundance and diversity with depth and gear type was similar, when 20 or 30 nets were used, but became more variable when only 10 nets were used, even with increased replication. We concluded that both trammel nets and gillnets should be included in a coastal biodiversity monitoring program, as each catches a different set of species, including both demersal and pelagic taxa. Further, we recommend using a minimum of 20 nets (ideally 30+) per station, with replication. The evaluated monitoring system has a minimal impact on the ecosystem, can be easily deployed using commercial vessels and effectively captures a large number of species, being thus, highly recommended to be used in coastal monitoring surveys.
- Preparation and characterization of Santa Barbara Amorphous-15 particles functionalized with mercaptopropyl groups and of their composites with poly(lactic acid)Publication . Díez-Rodríguez, Tamara M.; Blázquez-Blázquez, Enrique; Lourenço, João P.; Martínez, Juan C.; Cerrada, María L.; Pérez, ErnestoSanta Barbara Amorphous-15 (SBA-15) particles functionalized with mercaptopropyl groups (named as SBASH) have been prepared by a synthetic one-pot approach, and then have been incorporated into poly(lactic acid) (PLA), comparing their characteristics with those shown by composites attained with neat SBA-15 (PLASBA). The silica including the mercaptopropyl groups exhibits a certain loss of regularity because of its functionalization, although displays a better interaction with PLA than the pristine SBA-15 particles in the resulting materials. These composites (PLASBASH and PLASBA) also show a thermal stability slightly higher than neat PLA. An important nucleation effect of SBASH silica in the crystallization of PLA has been deduced from cooling experiments as well as from the cold crystallization in heating runs and from the degree of crystallinity reached. Small Angle X-ray Scattering (SAXS) profiles show that the PLA long spacings are rather similar for the different composites and the neat PLA. Thus, crystal size is rather similar in all samples. Microhardness values show an evident effect of reinforcement in all the composites compared with that shown by neat PLA. Nevertheless, the increase in rigidity is smaller in the biobased PLASBASH composites, those containing the modified silica, than in the PLASBA materials with the pristine SBA-15 particles.
- Biological traits and population dynamics for sustainable harvesting of Carcinus maenasPublication . Monteiro, João Nuno; Ovelheiro, Andreia; Maia, Francisco; Teodosio, Maria; Leitão, FranciscoResearch focusing on the biological patterns and population dynamics of Carcinus maenas has not been conducted for the purpose of fishery management along the European coastal systems. This has led to the implementation of fisheries management policies without scientific considerations, adversely affecting fishery profitability. To addrees this gap, we studied the crab species' population dynamics, reproductive biology, and growth patterns across different Portuguese lagoons and estuaries on a monthly basis from 2019 to 2021. Surveys were performed in the Southern (Ria Formosa lagoon and Ria Alvor estuary), Central (Sado river/estuary) and Northern regions (Ria Aveiro estuary) of Portugal. Monthly biological data was used to analyse size-frequency distributions, sex ratios, spawning seasons, recruitment pulses, estimate carapace width at first maturaty and biological growth parameters. It was observed that spawning occurs almost year-round in all systems, with a peak in the colder months, between September and March. In the southern regions of the Portuguese coast, the spawning period starts earlier than in the central and northern systems, with a higher sex ratio recorded for females in all systems. The carapace width at which 50 % (CW50) of individuals reach maturity is similar for both sexes, around 30 mm, a value below to the minimum landing size enforced in Portugal. The analysis of von Bertalanffy growth curves revealed a continuous recruitment with a peak during the colder months, with individuals reaching the size at maturation after six months. The fast growth and continuous recruitment leds to the existence of between four and six growth cohorts for both sexes across all system. The findings of this study can contribute to more effective fisheries management policies for C. maenas in Portugal, such as a reduction of the minimum landing size.
- Identification of stone deterioration patterns with large multimodal models. Definitions and benchmarkingPublication . Corradetti, Daniele; Rodrigues, José DelgadoThe conservation of stone-based cultural heritage sites is a critical concern for preserving cultural and historical landmarks. With the advent of Large Multimodal Models, as GPT-4omni (OpenAI), Claude 3 Opus (Anthropic) and Gemini 1.5 Pro (Google), it is becoming increasingly important to define the operational capabilities of these models. In this work, we systematically evaluate the image classification capabilities of the main foundational multimodal models to recognise and categorize anomalies and deterioration patterns of stone elements that are useful in the practice of conservation and restoration of world heritage. After defining a taxonomy of the main stone deterioration patterns and anomalies, we asked the foundational models to identify a curated selection of 354 highly representative images of stone-built heritage, offering them a careful selection of labels to choose from. The result, which varies depending on the type of pattern, allowed us to identify the strengths and weaknesses of these models in the field of heritage conservation and restoration.
- Sources and distribution of organic matter and polycyclic aromatic hydrocarbons in sediments of the southwestern Portuguese shelfPublication . Mil-Homens, Mário; Gonçalves, Sofia; Cortés, Alejandro; van Drooge, Barend L.; Stigter, Henko de; Grimalt, Joan O.; Cordeiro, Lívia; Santos, Miguel M.; Almeida, C. Marisa R.; Caetano, MiguelTotal organic carbon (Corg), total nitrogen (Ntot), Corg/Ntot, δ13Corg, δ15N, calcium carbonate (CaCO3), and grain size were analyzed in 70 surface samples and 19 short cores from the southwestern Portuguese shelf. Perylene and USEPA-16 PAHs were quantified in a subset of these samples. The findings suggest that organic matter derives from a mix of terrestrial and marine sources, outlined by Corg, Ntot, and isotopic signatures. Perylene combined with δ13Corg was used to identify the main PAH sources in these environments. Diagnostic perylene ratios revealed contributions from natural sources in the Tagus region and contaminated materials from the Sado Dredged Disposal Site, with additional perylene in Sines linked to atmospheric deposition of pyrogenic sources. A significant correlation between perylene and USEPA-16 PAHs indicates natural and anthropogenic inputs from the Tagus. This multiproxy approach—combining USEPA-16ΣPAHs, perylene, and δ13Corg—offers insights for assessing environmental risks and guiding marine environmental management according to the MSFD.
- Incised stone artefacts from the levantine middle palaeolithic and human behavioural complexityPublication . Goder-Goldberger, Mae; Marreiros, Joao; Paixão, Eduardo; Hovers, ErellaIn recent years, archaeological research has demonstrated the presence of abstract non-utilitarian behaviour amongst palaeolithic hominins, fuelling discussions concerning the origin and implications of such complex behaviours. A key component in these discussions is the aesthetic and symbolic character of intentionally incised artefacts. In this study, we emphasize the geometry of the incisions as clues to intentionality. Using 3D surface analysis, we characterised incisions found on a Levallois core from Manot cave, and on a flake and retouched blade from Amud cave. In addition, we applied the same methodology to the previously published engraved Levallois core from Qafzeh and the plaquette from Quneitra. The incisions on the Manot, Qafzeh and Quneitra artefacts show similar geometric characteristics. Notably in each of these cases, the incisions form patterns that align with the artefact's surface topography and shape. In contrast, the incisions on the Amud artefacts are shallower, with no clear orientation or patterning. The methodology applied thus creates a comparative context for MP incised items, reinforcing the interpretation of the Manot, Qafzeh and Quneitra artefacts as deliberate engravings, whereas the marks on the items from Amud are consistent with their functional use as abraders. While the Qafzeh, Quneitra and Manot items are isolated initiatives in their chronological and geographic contexts, the shared traits of the intentional engravings underscore their predetermined nature.
- Reconstruction of deep-water undercurrent variability from the outer Labrador Sea during the past 550,000 yearsPublication . Kaboth-Bahr, Stefanie; Bahr, André; Blaser, Patrick; Voelker, Antje; Lippold, Jörg; Gutjahr, Marcus; Hodell, David A.; Channell, James E.T.; Vernal, Anne de; Hillaire-Marcel, ClaudeWe present a comprehensive multi-proxy analysis spanning 550,000 years from the outer Labrador Sea region at the Integrated Ocean Drilling Program (IODP) Sites U1302/1303. We combine new benthic foraminiferal stable oxygen (delta 18O) and carbon (delta 13C) isotope records, with sediment elemental composition and authigenic neodymium isotope measurements, to provide insights into deep-water mass sourcing and changes of the Deep Western Boundary Current (DWBC), which exports North Atlantic Deep Water (NADW) into the wider North Atlantic as part of the lower limb of the Atlantic Meridional Overturning Circulation. We find that a prominent DWBC likely remained a persistent feature within the Labrador Sea region throughout the past 550 kyr. However, glacial peaks of marine isotope stage (MIS) 14 to MIS 2 were consistently characterized by a weaker or shallower DWBC, while all interglacial periods of MIS 13a to MIS 1, with the exception of MIS 7e, were marked by enhanced DWBC. Additionally, the dominant deep-water masses feeding into the DWBC during these glacial-interglacial periods varied from regional (K-rich sediment, unradiogenic epsilon Nd) to more distal sources from the Nordic Seas (Ti-rich sediment, radiogenic epsilon Nd). Yet, these changes in deep-water provenance did not consistently correlate with DWBC strength, suggesting that additional factors may have played a significant role in shaping the DWBC strength or core depth throughout the geological past.
- Marine forests forever—A necessary multilateral program for a fair futurePublication . Horta, Paulo; Sissini, Marina N.; Fonseca, Alessandra; Turra, Alexander; Rodrigues, Ana Claudia; Rorig, Leonardo; Bonomi‐Barufi, José; Pagliosa, Paulo; Bastos, Eduardo; Grimaldi, Guido; Dias, Carlos Eduardo Peixoto; Fialho, Fabio; Oliveira, Carlos Yure B.; Frade, Pedro R.; Schubert, Nadine; Silva, João; Assis, Jorge; Rossi, Sergio; Mansilla, Andres; Soares, Marcelo; Gouvêa, Lidiane; Alves-Lima, Cicero; A. G. Coelho, Márcio; Serrao, Ester A.; Anderson, Antonio Batista; Joyeux, Jean‐Christophe; Berchez, Flávio; Otero‐Ferrer, Francisco; Filho, Jorge Luiz Rodrigues; Mies, Miguel; Araujo, Moacyr; Hall‐Spencer, Jason M.Not only advances but also old addictions, setbacks, obstructions and delays are observed during COP16 (on biodiversity), COP29 (on climate change) and G20 in a year full of tragedies resulting from climate change; we need to look in the rearview mirror and plan new paths to be presented and discussed at COP30, in 2025, in the Brazilian Amazon. Worldwide temperature records show that 2023 and 2024 were the warmest in at least the last 2000 years (Esper, Torbenson, and Büntgen 2024). About 90% of the excess heat trapped by greenhouse gases and 30% of human emissions of carbon dioxide are stored in the ocean, shielding the planet from even more rapid changes in the biosphere. The recent acceleration in climate change is a threat not only to terrestrial systems but also to largely neglected marine ecosystems and their socio-biodiversity. Considering the relationship between global warming and biological extinctions (Malanoski et al. 2024), as well as the high vulnerability of marine biodiversity to these global threats (Pinsky et al. 2019), we call for the urgent need to create global and multilateral policies that are based on climate-smart ocean planning and carbon neutrality, focused on climate adaptation and mitigation strategies to protect, restore and foster sustainable management of marine socio-ecological systems (Frazão Santos et al. 2024).